In the USA, peak value of the AC voltage is around 175 V and the frequency is 60 Hz.

1. Find the numerical value of the RMS voltage for 60 Hz frequency.

2. Find the numerical value of the RMS voltage if the frequency is changed to 20 Hz?

3. Find the numerical value of the RMS voltage if the frequency is changed to 120 Hz?

Consider a large isothermal enclosure that is maintained at a uniform temperature of 2000 k. calculate the emissive power of the radiation that emerges from a small aperture on the enclosure surface. what is the wavelength ? , below which 10% of the emission is concentrated? what is the wavelength ? 2 above which 10% of the emission is concentrated? determine the wavelength at which maximum spectral emissive power occurs. what is the irradiation incident on a small object placed inside the enclosure?